Polymorphism and type casting in storage volume connections

ABSTRACT

Aspects of the disclosure provide for polymorphism and type casting in storage volume connections. A method of the disclosure includes receiving an identifier of a persistent volume (PV) created on a storage device and list of polymorphic connection types supported by the PV, creating a PV record for the PV at the container manager, responsive to receiving a query of the PV record from a container host, performing, for a connection from the container host to the storage device, type casting to select a connection type from the list of polymorphic connection types, and returning the identifier of the PV and connection information to cause the container host to establish the connection to the storage device via the selected connection type.

TECHNICAL FIELD

The implementations of the disclosure relate generally to computingsystems and, more specifically, to methods and systems for polymorphismand type casting in storage volume connections.

BACKGROUND

Container deployment faces multiple challenges in a hybrid cloudenvironment where baremetal and virtualized container hosts exist. Thisis especially true when connecting containers to backend storagesystems. On virtualized container host, containers can run inside avirtual machine (VM). In this case block storage is presented to the VMand containers by a hypervisor that masks detailed storage connectioninformation. On the other hand, when containers are running on remotebaremetal container hosts, the containers have to connect to the samestorage asset through a transport that the container host can initiate.In yet another case, the containers may run on a container host wherethe physical storage is collocated on the container host. In this case,the containers can use the local storage without having to initiate anyremote access protocols to connect.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be understood more fully from the detaileddescription given below and from the accompanying drawings of variousimplementations of the disclosure. The drawings, however, should not betaken to limit the disclosure to the specific implementations, but arefor explanation and understanding only.

FIG. 1 is a block diagram illustrating example computer systemsaccording to implementations of the disclosure;

FIG. 2 illustrates a flow of operations for polymorphism and typecasting for storage volume connections according to an implementation ofthe disclosure;

FIG. 3 depicts a block diagram of a computer system operating inaccordance with one or more aspects of the disclosure;

FIG. 4 a block diagram of a computer system operating in accordance withone or more aspects of the disclosure;

FIG. 5 is a flow diagram illustrating a method for polymorphism and typecasting in storage volume connections as applied by a container manager,according to an implementation of the disclosure;

FIG. 6 is a flow diagram illustrating a method for polymorphism and typecasting in storage volume connections as applied by a container host,according to an implementation of the disclosure;

FIG. 7 is a flow diagram illustrating another method for polymorphismand type casting in storage volume connections as applied by a containermanager, according to an implementation of the disclosure;

FIG. 8 is a flow diagram illustrating a method for polymorphism and typecasting in storage volume connections with an optimization as applied bya container manager, according to an implementation of the disclosure;

FIG. 9 is a flow diagram illustrating a method for polymorphism and typecasting in storage volume connections with an optimization as applied bya container host, according to an implementation of the disclosure; and

FIG. 10 illustrates a block diagram of one implementation of a computersystem.

DETAILED DESCRIPTION

Aspects of the disclosure provide for systems and methods forpolymorphism and type casting in storage volume connections. Containerdeployment systems face multiple challenges in a hybrid cloudenvironment where baremetal and virtualized container hosts exist. Acontainer in a container deployment system may refer to an allocation,portioning, and assignment of host (compute) resources, such as centralprocessing unit (CPU) shares, network input/output (I/O), bandwidth,block I/O, and memory, in a way that these protected resources areisolated (or “contained”) so that that specific running services(processes) and namespaces may solely utilize them without interferingwith the rest of the system.

The challenges faced by container deployment systems in a hybrid cloudenvironment are especially apparent when connecting containers tobackend storage systems (storage devices). On virtualized containerhosts, containers can run inside a virtual machine (VM). In this case,block storage is presented to the VM and containers by a hypervisor thatmasks detailed storage connection information. On the other hand, whencontainers are running on remote baremetal container hosts, thecontainers have to connect to the same storage asset through a transportthat the container host can initiate. In yet another case, thecontainers may run on a container host where the physical storage iscollocated on the container host. In this case, the containers can usethe local storage without having to initiate any remote access protocolsto connect. These varied connection options corresponding to deployedcontainers can make connecting the containers to the backend storagesystem a complex process.

Implementations of the disclosure introduce polymorphism and typecasting for storage volume connections. In contrast to conventionalsystem's utilization of singleton and concrete types of storageconnection configurations, a polymorphic connection type is provided sothat access to the storage device can be determined on-the-fly (e.g., atruntime) by the container host. Examples of the polymorphic connectiontypes may include, but are not limited to, hypervisor initiated type,remote protocol access type, and local storage access type.Polymorphism, in programming languages and type theory, is the provisionof a single interface to entities of different types. In other words,subclasses of a class can define their own unique behaviors and yetshare some of the same functionality of the parent class.

A type casting mechanism is attached to the polymorphic connection type.Type casting refers to the act or result of changing an entity of onedata type into another. Each time a container host is to resolve theconnection type to the storage device, the container host passes itsnode information to a container manager that determines the appropriateconnection information from the polymorphic connection types andprovides this connection information to the container host. Thecontainer host then utilizes this connection information to establish aconnection to the storage device in order to access storage.

Utilization of the polymorphism and type casting for storage volumeconnections in container deployment systems can allow for automatedimplementation of varied connection protocols in a container deploymentsystem, without limiting the storage connection configuration options ofthe container host. This results in an improved connection process tobackend storage system, improved connection options available in thecontainer deployment system, and faster and more efficient performanceof the overall container deployment system.

FIG. 1 is a block diagram of an example of a container deployment system100 according to some implementations of the disclosure. “Containerdeployment system” as used herein may be and/or include one or morecomputing devices, where each computing device may comprise one or moreprocessors, one or more memory devices, and one or more input/output(I/O) interfaces.

As illustrated in FIG. 1, container deployment system 100 may includeone or more container hosts. 110, 120, 130, a container manager 140, anda storage device 150. As illustrated in FIG. 1, container hosts 110-130,container manager 140, and storage device 150 may be interconnected viaa network 105. Network 105 can include a private network (e.g., a localarea network (LAN)), a wide area network (WAN), intranet, etc.), apublic network (e.g., the Internet), etc.

Each of container hosts 110-130 and container manager 140 may includeprocessors (e.g., central processing units (CPUs)) communicativelycoupled to memory devices. Local connections within container hosts110-130 and container manager 140, including connections betweenprocessors and memory devices, may be provided by one or more localbuses (not shown) of a suitable architecture.

“Processor” or “processing device” as used herein may be and/or includea device capable of executing instructions encoding arithmetic, logical,or I/O operations. In one illustrative example, a processor may follow aVon Neumann architectural model and may comprise an arithmetic logicunit (ALU), a control unit, and a plurality of registers. In a furtheraspect, a processor may be a single core processor which is typicallycapable of executing one instruction at a time (or process a singlepipeline of instructions), or a multi-core processor which maysimultaneously execute multiple instructions. According to anotheraspect of the disclosure, a processor may be implemented as a singleintegrated circuit, two or more integrated circuits, or may be acomponent of a multi-chip module (e.g., in which individualmicroprocessor dies are included in a single integrated circuit packageand hence share a single socket). A processor may also be a centralprocessing unit (CPU) in some implementations.

“Memory device” herein may be and/or include a volatile or non-volatilememory device, such as RAM (random-access memory), ROM (read-onlymemory), EEPROM (electrically erasable programmable read-only memory),or any other device capable of storing data.

“I/O device” herein may be and/or include a device capable of providingan interface between a processor and an external device capable ofinputting and/or outputting binary data.

“Network interface controller” (NIC) herein may be and/or include acomputer hardware component that connects a computer to a computernetwork. An NIC may include electronic circuitry required to communicatewith other networked devices using specific physical layer and data linklayer standards.

As illustrated in FIG. 1, container hosts 110-130 may be implemented ina variety of different environments. Each of container hosts 110-130 isresponsible for deploying containers 115, 125, 135 in containerdeployment system 100. A container 115, 125, 135 is an allocation,portioning, and assignment of host (compute) resources, such as CPUshares, network I/O, bandwidth, block I/O, and memory (RAM), in a waythat these protected resources are isolated (or “contained”) so thatthat specific running services (processes) and namespaces may solelyutilize them without interfering with the rest of the system. Theprocesses may be lightweight Linux hosts based on a Linux image,multiple web servers and application, a single subsystem like a databasebackend, to a single process such as ‘echo “hello”’ with little to nooverhead. Containers 115, 125, 135 are sometimes referred to as“operating system-level virtualization” or “OS virtual environments” andthey differ from hypervisor-level virtualization. The container modeleliminates the hypervisor layer, redundant OS kernels, binaries, andlibraries used to run workloads in a VM.

Containers 115, 125, 135 may be hosted in a variety of differentenvironments, such as a hypervisor-based environment, a baremetalenvironment, or a hybrid-converged environment (having local storageaccess). These environments are represented, respectively, in FIG. 1 asVM container host 110, baremetal container host 120, andhybrid-converged container host 130.

VM container host 110 may deploy a container 115 within a VM 112 managedby a hypervisor 114. Hypervisor 114 is a software layer 150 (above thehardware and below the VMs) of the container host 110 that executes theVM. In implementations of the disclosure, a “VM” may also be referred toas a “guest” and these terms may be used interchangeably herein. Incertain implementations, hypervisor 114 may be a component of anoperating system (OS) executed by the VM container host 110.Alternatively, hypervisor 114 may be provided by an application runningunder the VM container host's 110 OS, or may run directly on thecorresponding VM container host 110 without an OS beneath it. Hypervisor114 may abstract the physical layer, including processors, memory, I/Odevices, etc. and present this abstraction to VM 112 as virtual devices,including virtual processors, virtual memory, virtual I/O devices, etc.A hypervisor 114 may abstract the physical layer and present thisabstraction to VM 112 to use, by providing interfaces between theunderlying hardware and virtual devices of VM 112.

Baremetal container host 120 may deploy a container 125 directly on thephysical components (CPUs, memory, etc.) of the baremetal container host120 without the use of a virtualization system. Hybrid-convergedcontainer host 130 may deploy a container 135, either in a virtualizedenvironment or directly on the hardware of the container host 130, whichis physically co-located with the storage device 132 it is to access.

Each of the container hosts 110-130 may execute a respective nodemanager 118, 128, 138. The node manager 118, 128, 138 may supportpolymorphism and type casting in storage volume connections inaccordance with one or more aspects of the disclosure, as describedfurther below. In certain implementations, a node manager 118, 128, 138may be implemented as a software component on the respective containerhost 110-130. Alternatively, functions of node manager 118, 128, 138 maybe performed by a hypervisor, such as hypervisor 114. In certainimplementations, a node manager 118, 128, 138 may be implemented as asoftware component of a guest OS invoked by a VM of the container host110-130. Alternatively, functions of node manager 118, 128, 138 may beperformed by a VM. In some implementations, node manager 118, 128, 138can implement one or more aspects of the disclosure as described inconnection with FIGS. 2-9.

In container deployment system 100, container hosts 110-130 may beprovisioned portions of storage resources, such as storage device 150 orlocal storage 132, to be consumed by the container hosts 110-130. In oneimplementation, storage device 150 and/or local storage 132 may be amemory (e.g., random access memory), a cache, a drive (e.g., a harddrive), a flash drive, a database system, or another type of componentor device capable of storing data. The storage device 150 and/or localstorage 132 may also include multiple storage components (e.g., multipledrives or multiple databases) that may also span multiple computingdevices (e.g., multiple server computers).

In one implementation, a container manager 140, communicably coupled tocontainer hosts 110-130, is responsible for managing the container hosts110-130 and the lifecycle of the containers 115, 125, 135 deployed oncontainer host 110-130. Container manager 140 may reside on a designatedcomputer system. Container manager 140 may be responsible forprovisioning new storage when added to the container deployment system100 and binding the provisioned storage to compute resources, such ascontainers 115, 125, 135, in the container deployment system 100. In oneimplementation, container manger 140 supports polymorphism and typecasting in storage volume connections, in accordance with one or moreaspects of the disclosure. In some implementations, container manager140 can implement one or more aspects of the disclosure as described inconnection with FIGS. 2-9.

For ease of explanation, the following description discusses storagedevice 150 in terms of implementations of the disclosure. However, thedescription provided similarly applies to local storage device 132 aswell.

Container manager 140 may include a storage manager 142 including avolume manager 143 and a type casting agent 145. When a storage device150 is added to container deployment system 100, the storage manager 142is responsible for configuring the storage device 150 for use bycontainers 115, 125, 135 in container deployment system 100. The volumemanager 142 of storage manger 142 may request to create persistentvolumes (PVs) 152 on the storage device 150. A PV 152 may refer to aportion of storage of the storage device 150 that has been provisionedby the storage manager 142. The PV 152 may include a directory and datawhich is accessible to the containers 115, 125, 135 to which it isassigned. How the directory comes to be, the medium that backs it, andthe contents of it are determined by the particular volume type (e.g.,iSCSI, cephfs, nfs, glusterfs, rbd, cloud provider specific storagesystem such as awsElasticBlockStore, etc.) used. A PV 152 may have alifecycle that is independent of the individual container(s) 115, 125,135 that use it. Although implementations of the disclosure specificallydiscuss persistent volumes (PVs), other types of storage resourcesconsumable by a container may be utilized in the polymorphism and typecasting in storage volume connections described herein.

In implementations of the disclosure, when the storage device 150creates the PV 152, it provides an identifier of the PV 152 as well as alist of polymorphic connection types (polymorphic connection type data155) supported by the PV 152. Examples of the polymorphic connectiontypes may include, but are not limited to, hypervisor initiated type,remote protocol access type, and local storage access type.Polymorphism, in programming languages and type theory, is the provisionof a single interface to entities of different types. In other words,subclasses of a class can define their own unique behaviors and yetshare some of the same functionality of the parent class. For example,in the Java programming language, runtime polymorphism is also referredto as dynamic method dispatch and is a mechanism by which a call to anoverridden method is resolved at runtime. When an overridden method iscalled by a reference, Java programming language determines whichversion of the method to execute based on the type of object it referredto. In implementations of the disclosure, each PV 152 is polymorphic inthe sense that each PV 152 is associated with one or more differentconnection protocols represented by different classes.

The volume manager 143 creates PV records 144 for each created PV 152provided by storage device 150, where the PV records 144 specify theidentifier of the PV, other configuration information of the PV 152(e.g., storage capacity, etc.), and the supported polymorphic connectiontypes of the PV 152.

In implementations of the disclosure, the polymorphic connection typedata 155 is provided so that access to the storage can be determined onthe fly (e.g., at runtime) by the container host 110, 120 130. Theprotocol utilized to establish a communication connection between acontainer host 110-130 and storage device 150 in order for the container115, 125, 135 to consume the PV 152 varies depending on the type ofenvironment of the container host (e.g., hypervisor-based, baremetal,hybrid-converged). For example, the protocol to establish a connectionbetween a container 115 executing on a VM 112 in VM container host 110is different from the protocol used to establish a connection between acontainer 125 executing on baremetal container host 120, which isdifferent from the protocol used to establish a connection between acontainer 135 executing in a local storage access environment ofhybrid-converged container host 130.

In one implementation, when a container host 110-130 seeks to consume(e.g., mount) a storage resource (such as PV 152), the node manager 118,128, 138 of the container host 110-130 sends a query for the PV record144 including a PV identifier and node information of the container host110-130. The query is an attempt to resolve the connection type to useto connect to the storage device 150. Node manager 118, 128, 138 may beaware of the PV identifier as a result of a claiming process performedby the storage manager 142 and node manager 118, 128, 138. The claimingprocess includes binding created PVs 152 to requests for storage(referred to as persistent volume claims or “claims”) generated by nodemanager 118, 128, 138 for containers 115, 125, 135. A claim may be arequest for a specific size and access mode (e.g., read/write, readonly, etc.) of storage. Storage manager 143 may match a node manager's118, 128, 138 claim to provisioned PVs 152 and bind the PV and claimtogether. The node manager 118, 128, 138 is informed of the PVs 152(e.g., a PV identifier is provided) that are bound to claims of the nodemanager 118, 128, 138.

A type casting agent 145 of the storage manager 142 receives the PVrecord query from the node manager 118, 128, 138 and performs typecasting to identify an appropriate connection type for the containerhost 110-130. Type casting refers to the act or result of changing anentity of one data type into another. The type casting agent 145 mayreceive the PV identifier and node information from the query and usethis information to determine the connection protocol for the containerhost 110-130 to use to connect to the storage device 150. The nodeinformation may include, but is not limited to, an identity of the node(e.g., hostname, IP address, etc.), the cloud configuration (e.g., AWS,Azure, OpenStack, etc.), and machine configuration (OS distribution,kernel version, supported storage connection types, etc.).

The type casting agent 145 compares the node information to the list ofpolymorphic connection types of the PV record 144 corresponding to thePV identifier, and, based on this comparison, selects the connectionprotocol (i.e., selects one of the classes from the polymorphicconnection types) that corresponds to the environment of the containerhost 110-130 as discerned from the provided node information. The typecasting agent 145 then returns the PV 152 identifier and connectioninformation for the chosen connection type to the node manager 118, 128,138.

In one example, the type casting agent 145 may determine, based on thenode information, that connection protocol for the VM container host 110is a hypervisor initiated protocol type. As such, the type casting agent145 type casts the connection protocol for the hypervisor and returnsthis connection information to the node manager 118. In oneimplementation, the connection information for the hypervisor-initiatedprotocol type includes a device ID of the storage device 150. Thehypervisor 114 at the VM container host 110 can then utilize the deviceID to connect to the storage device 150.

In another example, the type casting agent 145 may determine, based onthe node information, that connection protocol for the baremetalcontainer host 120 is a remote access protocol type. As such, the typecasting agent 145 type casts the connection protocol for the baremetaldevice and returns this connection information to the node manager 128.In one implementation, the connection information for the remote accessprotocol type includes a name of the protocol (e.g., iSCSI, NFS, etc.)to use to connect to the storage device 150. The baremetal containerhost 120 can then determine whether it has the capability to connect tothe storage device 150 using the identified protocol and, if so, utilizethe protocol to connect to the storage device 150.

In a further example, the type casting agent 145 may determine, based onthe node information, that connection protocol for the hybrid-convergedcontainer host 130 is a local storage access protocol type. As such, thetype casting agent 145 type casts the connection protocol for thehybrid-converged container host 130 and returns this connectioninformation to the node manager 138. In one implementation, theconnection information for the local storage access protocol typeincludes a location (e.g., host name or IP address) of the storagedevice 132. The hybrid-converged container host 130 can then utilize thelocation information to determine that the location information matchesits own location information, and then use the device path in theconnection information to connect to the storage device 132.

Once the connection information is received, the node manager 118, 128,138 can then cause a connection to the storage device 150 to beinitiated using the connection protocol that is based on the receivedconnection information. Once the connection is established, the storagedevice 150 responds to the container host 110-130 and provides access tothe PV 152.

In some implementations, the polymorphic connection type may be furtherextended and optimized to type cast additional types of connectionprotocols based on features beyond the environment of the container host110-130. For example, the polymorphic connection types may furtherinclude secure connection protocols, such as encrypted iSCSI, that canbe used when the type casting conditions indicate that the containerhost 110-130 is sensitive to data security issues (e.g., demilitarizedzones (DMZ) or trusted network). In another example, the polymorphicconnection types may include high-performance connection protocols, suchas iSER, that can be used when the type casting conditions indicate thatthe container host 110-130 is performance sensitive. In theimplementations using the extended polymorphic connection types, thecontainer manager 140 may examine, in addition to the environment of thecontainer host 1101-30, the particular type of compute job that is beingrequests (e.g., secure or high-performance). Additional extensions tothe polymorphic connection types may be implemented beyond security andperformance that recognize other factors that impact the containerdeployment system 100.

FIG. 2 illustrates a flow of operations 200, using an example Kubernetesenvironment, for polymorphism and type casting for storage volumeconnections according to an implementation of the disclosure. In someimplementations, process 200 may be performed by a container host 201, acontainer manager 202, and a storage device 203. Container host may beany of VM container host 110, baremetal container host 120, orhybrid-converged container host 130, as described with respect toFIG. 1. Container manger 202 may be the same as container manager 140,as described with respect to FIG. 1. Storage device 203 may be the sameas storage device 150 or local storage 132, as described with respect toFIG. 1.

As shown in FIG. 2, process 200 begins at 210 where the containermanager 202 requests to create a PV and sends this request to thestorage device 203. Then, at 220, the storage device returns a PV and alist of polymorphic connection types to the container manager 202. Inone implementation, the polymorphic connection types may include, butare not limited to, hypervisor-initiated type, remote protocol accesstype, and local storage access type. In some implementations, thepolymorphic connection types may be further extended to include secureand/or high-performance protocols as well.

At 230, the container manager 202 creates one or more PC records inresponse to receiving the PV and the list of polymorphic connectiontypes. At 240, the compute node 201 queries the PV record of thecontainer manager 202 using the PV name and node information of thecontainer host 201. At 250, the container manager 202, in response tothe query from the container host 201, performs connection type castingby examining the node information and choosing an appropriate connectiontype.

Subsequently, at 260, the container manager 202 returns the PV and theconnection information for the chosen connection type to the containerhost 201. The, at 270, the container host 201 initiates the connectionto the storage device 203 based on the received connection information.Lastly, at 280, the storage device 203 responds to the initiator (e.g.,the container host 201) of the connection and provides storage access.

FIG. 3 depicts a block diagram of a computer system that is a containerhost 300 operating in accordance with one or more aspects of thedisclosure. Container host 300 may be the same or similar to containerhost 1110, 120, 130 of FIG. 1 and may include one or more processingdevices 301 and one or more memory devices 350. In the example shown,container host 300 may include components and modules for polymorphismand type casting in storage volume connections.

The container host 300 may include a memory 350 that can store one ormore a query 355. The memory 350 may be and/or include a volatile ornon-volatile memory device, such as RAM (random-access memory), ROM(read-only memory), EEPROM (electrically erasable programmable read-onlymemory), or any other device capable of storing data.

The container host 300 may include a processing device 301 thatimplements polymorphism and type cast for storage volume connectionsaccording to implementations of the disclosure. The container host 300may be communicably coupled to a container manager 360 and a storagedevice 370 via a network or other connection.

The processing device 301 may include a query transmitter 310, aninformation receiver 320, and a connection initiator 330. The querytransmitter 310 may transmit, to a container manager 360, a query 355for a PV record maintained by the container manager 360. The query 355may include a name 352 of the PV and node information 354 of thecontainer host 300.

The information receiver may receive, from the container manager 360, anidentifier of the PV 325 and connection information 327. The connectioninformation 327 is specific to a connection type, where the connectiontype is type casted by the container manager 360, using the nodeinformation 354, from a plurality of polymorphic connection typessupported by the PV. The connection initiator 330 may establish, usingthe connection information 327, a connection to the storage device 370via the connection type.

FIG. 4 depicts a block diagram of a computer system 400 operating inaccordance with one or more aspects of the disclosure. Computer system400 may be the same or similar to container manager 140 of FIG. 1 andmay include one or more processing devices 401 and one or more memorydevices 450. In the example shown, computer system 400 may includecomponents and modules for polymorphism and type casting in storagevolume connections.

The computer system 400 may include a memory 450 that can store one ormore PV records 455. The PV record 455 may correspond to PVs 465 createdon a storage device 460 communicably coupled to the computer system 400via a network 405 or other connection. The PV record 455 includes a PVidentifier 452 and a list of polymorphic connection types 454 supportedby the PV 465 corresponding to the PV record 455. The memory 450 may beand/or include a volatile or non-volatile memory device, such as RAM(random-access memory), ROM (read-only memory), EEPROM (electricallyerasable programmable read-only memory), or any other device capable ofstoring data.

The computer system 400 may include a processing device 401 thatexecutes a container manager 402. Container manager 402 may be the sameas container manager 140 describes with respect to FIG. 1. The containermanager 402 may implement polymorphism and type casting in storagevolume connections. The container manager 402 may include a queryreceiver 410, a type casting agent 420, connection information 430, andan information transmitter 440.

The query receiver 410 may receive a query for one of the PV records 455from a container host 470 communicably coupled to the computer system400 via a network 405 or other connection. The type casting agent 420may perform type casting associated with a connection from the containerhost 470 to the storage device 460. Performing the type casting at thetype casting agent 420 may include a connection type selector 425 of thetype casting agent 420 selecting a connection type from the list ofpolymorphic connection types 454 in view of node information of thecontainer host 475 comprised in the query.

The information transmitter 440 may transmit, to the container host 470in response to the query, the identifier of the PV 452 and connectioninformation 430 to cause the container host 470 to establish theconnection to the storage device 460 via the selected connection type.The connection information 430 is different for each of the polymorphicconnection types.

FIG. 5 is a flow diagram illustrating a method 500 for polymorphism andtype casting in storage volume connections as applied by a containermanager, according to an implementation of the disclosure. Method 500can be performed by processing logic that may comprise hardware (e.g.,circuitry, dedicated logic, programmable logic, microcode, etc.),software (such as instructions run on a processing device), firmware, ora combination thereof. In one implementation, method 500 is performed bya processing device (e.g. a processing device 1002 of FIG. 10) asdescribed in connection with FIG. 1. In some implementations, method 500can be performed by container manager 140 described with respect to FIG.1.

For simplicity of explanation, the methods of this disclosure aredepicted and described as a series of acts. However, acts in accordancewith this disclosure can occur in various orders and/or concurrently,and with other acts not presented and described herein. Furthermore, notall illustrated acts may be required to implement the methods inaccordance with the disclosed subject matter. In addition, those skilledin the art will understand and appreciate that the methods couldalternatively be represented as a series of interrelated states via astate diagram or events. Additionally, it should be appreciated that themethods disclosed in this specification are capable of being stored onan article of manufacture to facilitate transporting and transferringsuch methods to computing devices. The term “article of manufacture,” asused herein, is intended to encompass a computer program accessible fromany computer-readable device or memory page media.

Referring to FIG. 5, method 500 begins at block 510 where the processingdevice performs one or more operations to receive an identifier of a PVcreated on a storage device and list of polymorphic connection typessupported by the PV. At block 520, the processing device creates a PVrecord for the PV at the container manager. At block 530, the processingdevice performs, responsive to receiving a query of the PV record from acontainer host, type casting associated with a connection from thecontainer host to the storage device. In one implementation, performingthe type casting comprises selecting a connection type from the list ofpolymorphic connection types in view of node information of thecontainer host comprised in the query.

Lastly, at block 540, the processing device returns, to the containerhost in response to the query, the identifier of the PV and connectioninformation to cause the container host to establish the connection tothe storage device via the selected connection type. In oneimplementation, the connection information is different for each of thepolymorphic connection types.

FIG. 6 is a flow diagram illustrating a method 600 for polymorphism andtype casting in storage volume connections as applied by a containerhost, according to an implementation of the disclosure. Method 600 canbe performed by processing logic that may comprise hardware (e.g.,circuitry, dedicated logic, programmable logic, microcode, etc.),software (such as instructions run on a processing device), firmware, ora combination thereof. In one implementation, method 600 is performed bya processing device (e.g. a processing device 1002 of FIG. 10) asdescribed in connection with FIG. 1. In some implementations, method 600can be performed by a source hypervisor running on the source computersystem. In some implementations, method 600 can be performed by any ofcontainer hosts 1101-30 described with respect to FIG. 1.

Referring to FIG. 6, method 600 begins at block 610 where the processingdevice performs one or more operations to transmit, to a containermanager, a query for a persistent volume (PV) record maintained by thecontainer manager, the query comprising a name of the PV and nodeinformation of a container host including the processing device.

At block 620, the processing device receives, from the containermanager, an identifier of the PV and connection information. In oneimplementation, the connection information is specific to a connectiontype. In addition, the connection type is type casted by the containermanager, using the node information, from a plurality of polymorphicconnection types supported by the PV. Lastly, at block 630, theprocessing device establishes, using the connection information, aconnection to the storage device via the connection type.

FIG. 7 is a flow diagram illustrating another method 700 forpolymorphism and type casting in storage volume connections as appliedby a container manager, according to an implementation of thedisclosure. Method 700 can be performed by processing logic that maycomprise hardware (e.g., circuitry, dedicated logic, programmable logic,microcode, etc.), software (such as instructions run on a processingdevice), firmware, or a combination thereof. In one implementation,method 700 is performed by a processing device (e.g. a processing device1002 of FIG. 10) as described in connection with FIG. 1. In someimplementations, method 700 can be performed by container manager 140described with respect to FIG. 1.

Method 700 can begin at block 710 where the processing device executes acontainer manager to manage one or more containers on one or morecontainer hosts. At block 720, the processing device performs,responsive to receiving a query for a PV record from a container host,perform type casting associated with a connection from the containerhost to the storage device. In one implementation, performing the typecasting includes selecting a connection type from the list ofpolymorphic connection types in view of node information of thecontainer host comprised in the query. Furthermore, the PV record maycorrespond to a PV created on a storage device, wherein the PV recordcomprises a PV identifier and a list of polymorphic connection typessupported by the PV corresponding to the PV record.

Lastly, at block 730, the processing device transmits, to the containerhost in response to the query, the identifier of the PV and connectioninformation to cause the container host to establish the connection tothe storage device via the selected connection type. In oneimplementation, the connection information is different for each of thepolymorphic connection types.

FIG. 8 is a flow diagram illustrating a method 800 for polymorphism andtype casting in storage volume connections with an optimization asapplied by a container manager, according to an implementation of thedisclosure. Method 800 can be performed by processing logic that maycomprise hardware (e.g., circuitry, dedicated logic, programmable logic,microcode, etc.), software (such as instructions run on a processingdevice), firmware, or a combination thereof. In one implementation,method 800 is performed by a processing device (e.g. a processing device1002 of FIG. 10) as described in connection with FIG. 1. In someimplementations, method 800 can be performed by container manager 140described with respect to FIG. 1.

Method 800 begins at block 810 where the processing device performs oneor more operations to execute a container manager to manage one or morecontainers on one or more container hosts. Then, at block 820, theprocessing device receives a query for a PV record from a containerhost. In one implementation, the query includes a PV name and nodeinformation of the container host, and a job type of the container host.

Subsequently, at block 830, the processing device performs, responsiveto receiving the query, type casting associated with a connection fromthe container host to the storage device. In one implementation,performing the type casting comprises selecting a connection type from alist of polymorphic connection types in the PV record in view of thenode information of the container host and the job type.

Lastly, at block 840, the processing device transmits, to the containerhost in response to the query, an identifier of the PV from the PVrecord and connection information to cause the container host toestablish the connection to the storage device via the selectedconnection type. In one implementation, the connection information isdifferent for each of the polymorphic connection types and job types.

FIG. 9 is a flow diagram illustrating a method 900 for polymorphism andtype casting in storage volume connections with an optimization asapplied by a container host, according to an implementation of thedisclosure. Method 900 can be performed by processing logic that maycomprise hardware (e.g., circuitry, dedicated logic, programmable logic,microcode, etc.), software (such as instructions run on a processingdevice), firmware, or a combination thereof. In one implementation,method 900 is performed by a processing device (e.g. a processing device1002 of FIG. 10) as described in connection with FIG. 1. In someimplementations, method 900 can be performed by any of container hosts110-130 described with respect to FIG. 1.

Method 900 begins at block 910 where the processing device transmits, toa container manager, a query for a PV record maintained by the containermanager. In one implementation, the query comprising a PV name and nodeinformation of the container host, and a job type of the container host.

At block 920, the processing device receives, from the containermanager, an identifier of the PV and connection information. In oneimplementation, the connection information is specific to a connectiontype and the job type. The connection type may be type casted by thecontainer manager, using the node information and the job type, from aplurality of polymorphic connection types supported by the PV. Lastly,at block 930, the processing device establishes, using the connectioninformation, a connection to the storage device via the connection type.

FIG. 10 illustrates a diagrammatic representation of a machine in theexample form of a computer system 1000 within which a set ofinstructions, for causing the machine to perform any one or more of themethodologies discussed herein, may be executed. In alternativeimplementations, the machine may be connected (e.g., networked) to othermachines in a LAN, an intranet, an extranet, or the Internet. Themachine may operate in the capacity of a server or a client device in aclient-server network environment, or as a peer machine in apeer-to-peer (or distributed) network environment. The machine may be apersonal computer (PC), a tablet PC, a set-top box (STB), a PersonalDigital Assistant (PDA), a cellular telephone, a web appliance, aserver, a network router, switch or bridge, or any machine capable ofexecuting a set of instructions (sequential or otherwise) that specifyactions to be taken by that machine. Further, while a single machine isillustrated, the term “machine” shall also be taken to include anycollection of machines that individually or jointly execute a set (ormultiple sets) of instructions to perform any one or more of themethodologies discussed herein.

The computer system 1000 includes a processing device 1002 (e.g.,processor, CPU, etc.), a main memory 1004 (e.g., read-only memory (ROM),flash memory, dynamic random access memory (DRAM) (such as synchronousDRAM (SDRAM) or DRAM (RDRAM), etc.), a static memory 1006 (e.g., flashmemory, static random access memory (SRAM), etc.), and a data storagedevice 1018, which communicate with each other via a bus 1008.

Processing device 1002 represents one or more general-purpose processingdevices such as a microprocessor, central processing unit, or the like.More particularly, the processing device may be complex instruction setcomputing (CISC) microprocessor, reduced instruction set computer (RISC)microprocessor, very long instruction word (VLIW) microprocessor, orprocessor implementing other instruction sets, or processorsimplementing a combination of instruction sets. Processing device 1002may also be one or more special-purpose processing devices such as anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA), a digital signal processor (DSP), network processor,or the like. The processing device 1002 is configured to execute theprocessing logic 426 for performing the operations and steps discussedherein.

The computer system 1000 may further include a network interface device1022 communicably coupled to a network 1064. The computer system 1000also may include a video display unit 1010 (e.g., a liquid crystaldisplay (LCD) or a cathode ray tube (CRT)), an alphanumeric input device1012 (e.g., a keyboard), a cursor control device 1014 (e.g., a mouse),and a signal generation device 1020 (e.g., a speaker).

The data storage device 1018 may include a machine-accessible storagemedium 1024 on which is stored software 1026 embodying any one or moreof the methodologies or functions described herein. The software 1026may also reside, completely or at least partially, within the mainmemory 1004 as instructions 1026 and/or within the processing device1002 as processing logic 1026 during execution thereof by the computersystem 1000; the main memory 1004 and the processing device 1002 alsoconstituting machine-accessible storage media.

The machine-readable storage medium 1024 may also be used to storeinstructions 1026 to implement a type casting agent 1090 and/or asoftware library containing methods that call the above applications.Type casting agent 1090 can implement polymorphism and type casting instorage volume connections by performing one or more operationsdescribed in connection with FIGS. 1-9 above. While themachine-accessible storage medium 1024 is shown in an exampleimplementation to be a single medium, the term “machine-accessiblestorage medium” should be taken to include a single medium or multiplemedia (e.g., a centralized or distributed database, and/or associatedcaches and servers) that store the one or more sets of instructions. Theterm “machine-accessible storage medium” shall also be taken to includeany medium that is capable of storing, encoding or carrying a set ofinstruction for execution by the machine and that cause the machine toperform any one or more of the methodologies of the disclosure. The term“machine-accessible storage medium” shall accordingly be taken toinclude, but not be limited to, solid-state memories, and optical andmagnetic media.

Other computer system designs and configurations may also be suitable toimplement the system and methods described herein. The followingexamples illustrate various implementations in accordance with one ormore aspects of the disclosure.

The following examples pertain to further embodiments. Example 1 is amethod for polymorphism and type casting in storage volume connectionscomprising receiving, by a processing device executing a containermanager, an identifier of a persistent volume (PV) created on a storagedevice and list of polymorphic connection types supported by the PV,creating a PV record for the PV at the container manager, and responsiveto receiving a query of the PV record from a container host, performingtype casting associated with a connection from the container host to thestorage device, wherein performing the type casting comprises selectinga connection type from the list of polymorphic connection types in viewof node information of the container host comprised in the query.Further to Example 1, the method additionally comprises returning, tothe container host in response to the query, the identifier of the PVand connection information to cause the container host to establish theconnection to the storage device via the selected connection type,wherein the connection information is different for each of thepolymorphic connection types.

In Example 2, the subject matter of Example 1 can optionally includewherein the PV record comprises at least one of the identifier of thePV, a storage capacity of the PV, the polymorphic connection typessupported by the PV, or access mode of the PV. In Example 3, the subjectmatter of any one of Examples 1-2 can optionally include wherein thenode information comprises at least one of a node identifier, cloudconfiguration information, and machine configuration information. InExample 4, the subject matter of any one of Examples 1-3 can optionallyinclude wherein the connection types comprise at least one of ahypervisor type, a remote access protocol type, or a local volume type.

In Example 5, the subject matter of any one of Examples 1-4 canoptionally include wherein the hypervisor type indicates a container ofthe container host is implemented on a virtual machine managed by ahypervisor of the container host. In Example 6, the subject matter ofany one of Examples 1-5 can optionally include wherein the connectioninformation comprises a device identifier (ID) of the storage device,the device ID used by the hypervisor to establish the connection to thestorage device.

In Example 7, the subject matter of any one of Examples 1-6 canoptionally include wherein the remote access protocol type indicates acontainer of the container host is implemented on baremetal componentsof the container host. In Example 8, the subject matter of any one ofExamples 1-7 can optionally include wherein the connection informationcomprises an identification of a connection protocol for the containerhost to use to establish the connection to the storage device. InExample 9, the subject matter of any one of Examples 1-8 can optionallyinclude wherein the local volume type indicates a container of thecontainer host is co-located with the storage device on the containerhost.

In Example 10, the subject matter of any one of Examples 1-9 canoptionally include wherein the connection information comprises alocation of the storage device, the location used to identify a devicepath used by the compute to establish the connection to the storagedevice, wherein the location comprises at least one of a host name or anInternet Protocol (IP) address of the storage device.

Example 11 is a non-transitory computer-readable medium for implementingpolymorphism and type casting in storage volume connections. In Example11, the non-transitory machine-readable medium includes instructionsthat, when executed by a processing device, cause the processing deviceto transmit, by the processing device to a container manager, a queryfor a persistent volume (PV) record maintained by the container manager,the query comprising a name of the PV and node information of acontainer host comprising the processing device. In Example 11, theprocessing device is further to receive, by the processing device fromthe container manager, an identifier of the PV and connectioninformation, wherein the connection information is specific to aconnection type, and wherein the connection type is type casted by thecontainer manager, using the node information, from a plurality ofpolymorphic connection types supported by the PV, and establish, by theprocessing device using the connection information, a connection to thestorage device via the connection type.

In Example 12, the subject matter of Example 11 can optionally includewherein the PV record comprises at least one of the identifier of thePV, a storage capacity of the PV, the polymorphic connection typessupported by the PV, or access mode of the PV. In Example 13, thesubject matter of Examples 11-12 can optionally include wherein the nodeinformation comprises at least one of a node identifier, cloudconfiguration information, and machine configuration information.

In Example 14, the subject matter of Examples 11-13 can optionallyinclude wherein the connection types comprise at least one of ahypervisor type, a remote access protocol type, or a local volume type.In Example 15, the subject matter of Examples 11-14 can optionallyinclude wherein the hypervisor type indicates a container of thecontainer host is implemented on a virtual machine managed by ahypervisor of the container host, and wherein the connection informationcomprises a device identifier (ID) of the storage device, the device IDused by the hypervisor to establish the connection to the storagedevice.

In Example 16, the subject matter of Examples 11-15 can optionallyinclude wherein the remote access protocol type indicates a container ofthe container host is implemented on baremetal components of thecontainer host, and wherein the connection information comprises anidentification of a connection protocol for the container host to use toestablish the connection to the storage device. In Example 17, thesubject matter of Examples 11-16 can optionally include wherein thelocal volume type indicates a container of the container host isco-located with the storage device on the container host, and whereinthe connection information comprises a location of the storage device,the location used to identify a device path used by the compute toestablish the connection to the storage device, wherein the locationcomprises at least one of a host name or an Internet Protocol (IP)address of the storage device.

Example 18 is an apparatus for implementing polymorphism and typecasting in storage volume connections. In Example 18, the apparatusincludes a memory to store persistent volume (PV) records correspondingto PVs created on a storage device, wherein each PV record comprises aPV identifier and a list of polymorphic connection types supported bythe PV corresponding to the PV record. In Example 18, the apparatusfurther includes a processing device communicably coupled to the memory.Further to Example 18, the processing device can execute a containermanager to manage one or more containers on one or more container hostsand responsive to receiving a query for one of the PV records from acontainer host, perform type casting associated with a connection fromthe container host to the storage device, wherein performing the typecasting comprises selecting a connection type from the list ofpolymorphic connection types in view of node information of thecontainer host comprised in the query. In Example 18, the processingdevice can further transmit, to the container host in response to thequery, the identifier of the PV and connection information to cause thecontainer host to establish the connection to the storage device via theselected connection type, wherein the connection information isdifferent for each of the polymorphic connection types.

In Example 19, the subject matter of Example 18 can optionally includewherein the PV record comprises at least one of the identifier of thePV, a storage capacity of the PV, the polymorphic connection typessupported by the PV, or access mode of the PV. In Example 20, thesubject matter of Examples 18-19 can optionally include wherein the nodeinformation comprises at least one of a node identifier, cloudconfiguration information, and machine configuration information. InExample 21, the subject matter of Examples 18-20 can optionally includewherein the connection types comprise at least one of a hypervisor type,a remote access protocol type, or a local volume type.

In Example 22, the subject matter of Examples 18-21 can optionallyinclude wherein the hypervisor type indicates a container of thecontainer host is implemented on a virtual machine managed by ahypervisor of the container host, and wherein the connection informationcomprises a device identifier (ID) of the storage device, the device IDused by the hypervisor to establish the connection to the storagedevice.

In Example 23, the subject matter of Examples 18-22 can optionallyinclude wherein the remote access protocol type indicates a container ofthe container host is implemented on baremetal components of thecontainer host, and wherein the connection information comprises anidentification of a connection protocol for the container host to use toestablish the connection to the storage device. In Example 24, thesubject matter of Examples 18-23 can optionally include wherein thelocal volume type indicates a container of the container host isco-located with the storage device on the container host, and whereinthe connection information comprises a location of the storage device,the location used to identify a device path used by the compute toestablish the connection to the storage device, wherein the locationcomprises at least one of a host name or an Internet Protocol (IP)address of the storage device.

Example 25 is a system for implementing polymorphism and type casting instorage volume connections. In Example 20, the system includes a memoryand a processing device coupled to the memory. Further to Example 20,the processing device can execute a container manager to manage one ormore containers on one or more container hosts and receive a query for apersistent volume (PV) record from a container host, the querycomprising a PV name and node information of the container host, and ajob type of the container host. Further to Example 25, the processingdevice can responsive to receiving the query, perform type castingassociated with a connection from the container host to the storagedevice, wherein performing the type casting comprises selecting aconnection type from a list of polymorphic connection types in the PVrecord in view of the node information of the container host and the jobtype, and transmit, to the container host in response to the query, anidentifier of the PV from the PV record and connection information tocause the container host to establish the connection to the storagedevice via the selected connection type, wherein the connectioninformation is different for each of the polymorphic connection typesand job types.

In Example 26, the subject matter of Example 25 can optionally includewherein the PV record comprises at least one of the identifier of thePV, a storage capacity of the PV, the polymorphic connection typessupported by the PV, or access mode of the PV. In Example 27, thesubject matter of any one of Examples 25-26 can optionally includewherein the node information comprises at least one of a nodeidentifier, cloud configuration information, and machine configurationinformation.

In Example 28, the subject matter of any one of Examples 25-27 canoptionally include wherein the connection types comprise at least one ofa hypervisor type, a remote access protocol type, or a local volumetype, and wherein the job types comprise at least one of securitysensitive or performance sensitive. In Example 29, the subject matter ofany one of Examples 25-28 can optionally include wherein the hypervisortype indicates a container of the container host is implemented on avirtual machine managed by a hypervisor of the container host, andwherein the connection information comprises a device identifier (ID) ofthe storage device, the device ID used by the hypervisor to establishthe connection to the storage device.

In Example 30, the subject matter of any one of Examples 25-29 canoptionally include wherein the remote access protocol type indicates acontainer of the container host is implemented on baremetal componentsof the container host, and wherein the connection information comprisesan identification of a connection protocol for the container host to useto establish the connection to the storage device. In Example 31, thesubject matter of any one of Examples 25-30 can optionally includewherein the local volume type indicates a container of the containerhost is co-located with the storage device on the container host, andwherein the connection information comprises a location of the storagedevice, the location used to identify a device path used by the computeto establish the connection to the storage device, wherein the locationcomprises at least one of a host name or an Internet Protocol (IP)address of the storage device.

Example 31 is another method for polymorphism and type casting instorage volume connections comprising transmitting, by a processingdevice executing a container host to a container manager, a query for apersistent volume (PV) record maintained by the container manager, thequery comprising a PV name and node information of the container host,and a job type of the container host. Further to Example 1, the methodadditionally comprises receiving, by the processing device from thecontainer manager, an identifier of the PV and connection information,wherein the connection information is specific to a connection type andthe job type, and wherein the connection type is type casted by thecontainer manager, using the node information and the job type, from aplurality of polymorphic connection types supported by the PV, andestablishing, by the processing device using the connection information,a connection to the storage device via the connection type.

In Example 32, the subject matter of Example 31 can optionally includewherein the PV record comprises at least one of the identifier of thePV, a storage capacity of the PV, the polymorphic connection typessupported by the PV, or access mode of the PV. In Example 33, thesubject matter of any one of Examples 31-32 can optionally includewherein the node information comprises at least one of a nodeidentifier, cloud configuration information, and machine configurationinformation.

In Example 34, the subject matter of any one of Examples 31-33 canoptionally include wherein the connection types comprise at least one ofa hypervisor type, a remote access protocol type, or a local volumetype, and wherein the job type comprises at least one of securitysensitive or performance sensitive. In Example 35, the subject matter ofany one of Examples 31-34 can optionally include wherein the hypervisortype indicates a container of the container host is implemented on avirtual machine managed by a hypervisor of the container host, andwherein the connection information comprises a device identifier (ID) ofthe storage device, the device ID used by the hypervisor to establishthe connection to the storage device.

In Example 36, the subject matter of any one of Examples 31-35 canoptionally include wherein the remote access protocol type indicates acontainer of the container host is implemented on baremetal componentsof the container host, and wherein the connection information comprisesan identification of a connection protocol for the container host to useto establish the connection to the storage device. In Example 37, thesubject matter of any one of Examples 31-36 can optionally includewherein the local volume type indicates a container of the containerhost is co-located with the storage device on the container host, andwherein the connection information comprises a location of the storagedevice, the location used to identify a device path used by the computeto establish the connection to the storage device, wherein the locationcomprises at least one of a host name or an Internet Protocol (IP)address of the storage device.

Example 38 is an apparatus for implementing polymorphism and typecasting in storage volume connections comprising means for receiving anidentifier of a persistent volume (PV) created on a storage device andlist of polymorphic connection types supported by the PV, means forcreating a PV record for the PV at the container manager, means forperforming, responsive to receiving a query of the PV record from acontainer host, type casting associated with a connection from thecontainer host to the storage device, wherein performing the typecasting comprises selecting a connection type from the list ofpolymorphic connection types in view of node information of thecontainer host comprised in the query, and means for returning, to thecontainer host in response to the query, the identifier of the PV andconnection information to cause the container host to establish theconnection to the storage device via the selected connection type,wherein the connection information is different for each of thepolymorphic connection types. In Example 39, the subject matter ofExample 38 can optionally include the apparatus further configured toperform the method of any one of the Examples 1 to 37.

In the foregoing description, numerous details are set forth. It will beapparent, however, that the disclosure may be practiced without thesespecific details. In some instances, well-known structures and devicesare shown in block diagram form, rather than in detail, in order toavoid obscuring the disclosure.

Some portions of the detailed descriptions which follow are presented interms of algorithms and symbolic representations of operations on databits within a computer memory. These algorithmic descriptions andrepresentations are the means used by those skilled in the dataprocessing arts to most effectively convey the substance of their workto others skilled in the art. An algorithm is here, and generally,conceived to be a self-consistent sequence of steps leading to a desiredresult. The steps are those requiring physical manipulations of physicalquantities. Usually, though not necessarily, these quantities take theform of electrical or magnetic signals capable of being stored,transferred, combined, compared, and otherwise manipulated. It hasproven convenient at times, principally for reasons of common usage, torefer to these signals as bits, values, elements, symbols, characters,terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise, as apparent from the followingdiscussion, it is appreciated that throughout the description,discussions utilizing terms such as “sending,” “receiving,” “creating,”“assigning,” “providing,” “executing,” “removing,” “copying,” “storing,”“broadcasting,” “reassigning,” “storing,” “allocating,” “determining,”“associating,” or the like, refer to the action and processes of acomputer system, or similar electronic computing device, thatmanipulates and transforms data represented as physical (electronic)quantities within the computer system's registers and memories intoother data similarly represented as physical quantities within thecomputer system memories or registers or other such information storage,transmission or display devices.

The terms “first,” “second,” “third,” “fourth,” etc. as used herein aremeant as labels to distinguish among different elements and may notnecessarily have an ordinal meaning according to their numericaldesignation.

The disclosure also relates to an apparatus for performing theoperations herein. This apparatus may be specially constructed for thepurposes, or it may comprise a general purpose computer selectivelyactivated or reconfigured by a computer program stored in the computer.Such a computer program may be stored in a machine readable storagemedium, such as, but not limited to, any type of disk including floppydisks, optical disks, CD-ROMs, and magnetic-optical disks, read-onlymemories (ROMs), random access memories (RAMs), EPROMs, EEPROMs,magnetic or optical cards, or any type of media suitable for storingelectronic instructions, each coupled to a computer system bus.

The algorithms and displays presented herein are not inherently relatedto any particular computer or other apparatus. Various general purposesystems may be used with programs in accordance with the teachingsherein, or it may prove convenient to construct more specializedapparatus to perform the method steps. The structure for a variety ofthese systems will appear as set forth in the description below. Inaddition, the disclosure is not described with reference to anyparticular programming language. It will be appreciated that a varietyof programming languages may be used to implement the teachings of thedisclosure as described herein.

The disclosure may be provided as a computer program product, orsoftware, that may include a machine-readable medium having storedthereon instructions, which may be used to program a computer system (orother electronic devices) to perform a process according to thedisclosure. A machine-readable medium includes any mechanism for storingor transmitting information in a form readable by a machine (e.g., acomputer). For example, a machine-readable (e.g., computer-readable)medium includes a machine (e.g., a computer) readable storage medium(e.g., read only memory (“ROM”), random access memory (“RAM”), magneticdisk storage media, optical storage media, flash memory devices, etc.),etc.

Whereas many alterations and modifications of the disclosure will nodoubt become apparent to a person of ordinary skill in the art afterhaving read the foregoing description, it is to be understood that anyparticular implementation shown and described by way of illustration isin no way intended to be considered limiting. Therefore, references todetails of various implementations are not intended to limit the scopeof the claims, which in themselves recite only those features regardedas the disclosure.

What is claimed is:
 1. A method comprising: receiving, by a processingdevice executing a container manager, an identifier of a persistentvolume (PV) created on a storage device and a list of polymorphicconnection types supported by the PV; creating a PV record for the PV atthe container manager; responsive to receiving a query of the PV recordfrom a container host, performing, for a connection from the containerhost to the storage device, type casting to identify a connection typefrom the list of polymorphic connection types and connection informationfor the connection type to enable establishment of the connectionbetween the container host and the storage device, wherein theconnection information is different for each of the polymorphicconnection types; and returning, to the container host in response tothe query, the identifier of the PV and the connection information tocause the container host to establish the connection to the storagedevice via the connection type.
 2. The method of claim 1, wherein theconnection type is selected from the list of polymorphic connectiontypes in view of node information of the container host comprised in thequery.
 3. The method of claim 1, wherein the PV record comprises atleast one of the identifier of the PV, a storage capacity of the PV, thepolymorphic connection types supported by the PV, or access mode of thePV.
 4. The method of claim 2, wherein the node information comprises atleast one of a node identifier, cloud configuration information, ormachine configuration information.
 5. The method of claim 1, wherein thepolymorphic connection types comprise at least one of a hypervisor type,a remote access protocol type, or a local volume type.
 6. The method ofclaim 5, wherein the hypervisor type indicates a container of thecontainer host is implemented on a virtual machine managed by ahypervisor of the container host.
 7. The method of claim 6, wherein theconnection information comprises a device identifier (ID) of the storagedevice, the device ID used by the hypervisor to establish the connectionto the storage device.
 8. The method of claim 5, wherein the remoteaccess protocol type indicates a container of the container host isimplemented on baremetal components of the container host.
 9. The methodof claim 8, wherein the connection information comprises anidentification of a connection protocol for the container host to use toestablish the connection to the storage device.
 10. The method of claim5, wherein the local volume type indicates a container of the containerhost is co-located with the storage device on the container host. 11.The method of claim 10, wherein the connection information comprises alocation of the storage device, the location used to identify a devicepath used by the compute to establish the connection to the storagedevice, wherein the location comprises at least one of a host name or anInternet Protocol (IP) address of the storage device.
 12. Anon-transitory machine-readable storage medium including instructionsthat, when executed by a processing device, cause the processing deviceto: transmit, by the processing device to a container manager, a queryfor a persistent volume (PV) record maintained by the container manager,the query comprising a name of the PV and node information of acontainer host comprising the processing device; receive, by theprocessing device from the container manager, an identifier of the PVand connection information, wherein the connection information isspecific to a connection type that is type casted by the containermanager, using the node information, from a plurality of polymorphicconnection types supported by the PV, wherein the connection informationto enable establishment of the connection between the container host anda storage device storing the PV, wherein the connection information isdifferent for each of the polymorphic connection types; and establish,by the processing device using the connection information, a connectionto the storage device via the connection type.
 13. The non-transitorymachine-readable storage medium of claim 12, wherein the PV recordcomprises at least one of the identifier of the PV, a storage capacityof the PV, the polymorphic connection types supported by the PV, oraccess mode of the PV.
 14. The non-transitory machine-readable storagemedium of claim 12, wherein the node information comprises at least oneof a node identifier, cloud configuration information, or machineconfiguration information.
 15. The non-transitory machine-readablestorage medium of claim 12, wherein the polymorphic connection typescomprise at least one of a hypervisor type, a remote access protocoltype, or a local volume type.
 16. The non-transitory machine-readablestorage medium of claim 15, wherein the hypervisor type indicates acontainer of the container host is implemented on a virtual machinemanaged by a hypervisor of the container host, and wherein theconnection information comprises a device identifier (ID) of the storagedevice, the device ID used by the hypervisor to establish the connectionto the storage device.
 17. The non-transitory machine-readable storagemedium of claim 15, wherein the remote access protocol type indicates acontainer of the container host is implemented on baremetal componentsof the container host, and wherein the connection information comprisesan identification of a connection protocol for the container host to useto establish the connection to the storage device.
 18. Thenon-transitory machine-readable storage medium of claim 15, wherein thelocal volume type indicates a container of the container host isco-located with the storage device on the container host, and whereinthe connection information comprises a location of the storage device,the location used to identify a device path used by the container hostto establish the connection to the storage device, wherein the locationcomprises at least one of a host name or an Internet Protocol (IP)address of the storage device.
 19. An apparatus comprising: a memory tostore persistent volume (PV) records corresponding to PVs created on astorage device, wherein each PV record comprises a PV identifier and alist of polymorphic connection types supported by the PV correspondingto the PV record; and a processing device communicably coupled to thememory, to: execute a container manager to manage one or more containerson one or more container hosts; responsive to receiving a query for oneof the PV records from a container host of the one or more containerhosts, perform type casting associated with a connection from thecontainer host to the storage device, wherein performing the typecasting comprises identifying a connection type from the list ofpolymorphic connection types in view of node information of thecontainer host comprised in the query and identifying connectioninformation for the connection type to enable establishment of theconnection between the container host and the storage device, andwherein the connection information is different for each of thepolymorphic connection types; and transmit, to the container host inresponse to the query, the identifier of the PV and connectioninformation to cause the container host to establish the connection tothe storage device via the connection type, wherein the connectioninformation is different for each of the polymorphic connection types.20. The apparatus of claim 19, wherein the node information comprises atleast one of a node identifier, cloud configuration information, ormachine configuration information, and wherein the polymorphicconnection types comprise at least one of a hypervisor type, a remoteaccess protocol type, or a local volume type.